Wai Kim Lam, of Hong Kong, drowned while snorkelling off the Reef Experience vessel at Michaelmas Cay on the Great Barrier Reef, about 40 kilometres off Cairns on May 21, 2010.

The cause of death, the coroner found, was “drowning against a background of coronary artery atheroma”.

What happened in the aftermath, coroner Jane Bentley said, was obfuscation from the diving operator, Reef Encounter Enterprises sole director John Dennis Heuvel, which meant the question of whether proper safety procedures were followed on the Reef Experience remained unanswered.

Ms Bentley said Mr Heuval, also the sole director of Hostel Reef Trips Pty Ltd, refused to cooperate with the Office of Fair and Safe Work Queensland investigation into Mr Lam’s death.

He told investigators he had told his crew that providing statements to the OFSWQ or Queensland Police Service was “unlikely to be in their interests”.

Crew member Michael Chee refused to provide an initial statement following Mr Lam’s death, saying he had been directed otherwise, but was unwilling to say from whom he had received that advice.

Fellow crew member Cody Polglase failed to attend an appointment at which he had agreed to make a statement.

“The lack of information available to OFSWQ was a direct result of the lack of cooperation of Mr Polglase, Mr Chee and Mr Heuvel,” Ms Bentley said.

“Mr Chee and Mr Polglase both accepted in evidence (at the coronial inquest) that they knew that OFSWQ were seeking a statement from them.

“Neither could provide a reasonable explanation for why they did not provide a statement in the most serious circumstances – that is, where a passenger had died.

“Mr Heuvel and his companies failed to provide all information requested.

“Mr Heuvel, as the person responsible for the vessel and all that occurred on it that day, as well as being the lookout at the time of Mr Lam’s death, was a person who had information crucial to the OFSWQ investigation.”

Ms Bentley said the refusal of Mr Chee and Mr Polglase to provide information during the 2010 investigation meant the actual circumstances surrounding Mr Lam’s death may never be known.

“Had they given statements at the time, they may have indicated that proper procedures were followed,” she said.

“They were discouraged from doing so by Mr Heuvel, who was their employer, instructor and probably mentor at the time and undoubtedly had the ability to influence their decisions.”

Ms Bentley said it was “clear from the evidence” Mr Heuvel did not believe he should be subject to OFSWQ audits and was uncooperative with inspectors.

“Such an attitude, in a person responsible for vessels which have taken approximately 700,000 people to the reef and continue to take passengers, is unacceptable and poses a possible danger to public safety,” she said.

The inquest heard Mr Heuvel had tried to prevent police officers boarding his boat when another passenger – Shaun Corrigan – died in 2012, prompting one passenger to call out to him: “You’re an idiot, mate. Let them come on board to do their job.”

Ms Bentley recommended Mr Heuvel allow OFSWQ to conduct a comprehensive audit on all of his operations and that any refusal be reported to relevant authorities.

She also recommended the Australian Maritime Safety Authority  and Great Barrier Reef Marine Park Authority “consider reviewing” whether Mr Heuvel and his operations were fit to hold licenses to operate on the reef.